If you’re using React 0.13's shiny new class syntax… class MyComponent extends React.Component { }…remember, there is no auto-binding. class MyComponent extends React.Component { componentDidMount() { // `this` won't be what you think it is MyFluxStore.listen(this.onChange); } onChange(state) { // this is not this :( this.setState(state); } }An easy way to fix this is to use Function#bind. class M